add logs, javadoc and format to checkstyle conventions

cqrs/src/main/java/com/iluwatar/cqrs/commandes/CommandServiceImpl.java

@@ -8,6 +8,10 @@ import com.iluwatar.cqrs.domain.model.Author;
 import com.iluwatar.cqrs.domain.model.Book;
 import com.iluwatar.cqrs.util.HibernateUtil;
 
+/**
+ * This class is implementation of {@link ICommandService} interface. It uses Hibernate as an api for persistence.
+ *
+ */
 public class CommandServiceImpl implements ICommandService {
 
   private SessionFactory sessionFactory = HibernateUtil.getSessionFactory();

cqrs/src/main/java/com/iluwatar/cqrs/commandes/ICommandService.java

@@ -1,5 +1,9 @@
 package com.iluwatar.cqrs.commandes;
 
+/**
+ * This interface represents the commands of the CQRS pattern
+ *
+ */
 public interface ICommandService {
 
   public abstract void authorCreated(String username, String name, String email);

cqrs/src/main/java/com/iluwatar/cqrs/domain/model/Author.java

@@ -6,8 +6,7 @@ import javax.persistence.GenerationType;
 import javax.persistence.Id;
 
 /**
- * 
+ * This is an Author entity. It is used by Hibernate for persistence.
- * @author Sabiq Ihab
  *
  */
 @Entity
@@ -22,8 +21,11 @@ public class Author {
   /**
    * 
    * @param username
+   *          username of the author
    * @param name
+   *          name of the author
    * @param email
+   *          email of the author
    */
   public Author(String username, String name, String email) {
     super();

cqrs/src/main/java/com/iluwatar/cqrs/domain/model/Book.java

@@ -7,8 +7,7 @@ import javax.persistence.Id;
 import javax.persistence.ManyToOne;
 
 /**
- * 
+ * This is a Book entity. It is used by Hibernate for persistence. Many books can be written by one {@link Author}
- * @author Sabiq Ihab
  *
  */
 @Entity
@@ -24,8 +23,11 @@ public class Book {
   /**
    * 
    * @param title
+   *          title of the book
    * @param price
+   *          price of the book
    * @param author
+   *          author of the book
    */
   public Book(String title, double price, Author author) {
     super();

cqrs/src/main/java/com/iluwatar/cqrs/dto/Author.java

@@ -1,19 +1,33 @@
 package com.iluwatar.cqrs.dto;
 
-public class AuthorDTO {
+/**
+ * 
+ * This is a DTO (Data Transfer Object) author, contains only useful information to be returned
+ *
+ */
+public class Author {
 
   private String name;
   private String email;
   private String username;
 
-  public AuthorDTO(String name, String email, String username) {
+  /**
+   * 
+   * @param name
+   *          name of the author
+   * @param email
+   *          email of the author
+   * @param username
+   *          username of the author
+   */
+  public Author(String name, String email, String username) {
     super();
     this.name = name;
     this.email = email;
     this.username = username;
   }
 
-  public AuthorDTO() {
+  public Author() {
     super();
   }
 

cqrs/src/main/java/com/iluwatar/cqrs/dto/Book.java

@@ -1,17 +1,29 @@
 package com.iluwatar.cqrs.dto;
 
-public class BookDTO {
+/**
+ * 
+ * This is a DTO (Data Transfer Object) book, contains only useful information to be returned
+ *
+ */
+public class Book {
 
   private String title;
   private double price;
 
-  public BookDTO(String title, double price) {
+  /**
+   * 
+   * @param title
+   *          title of the book
+   * @param price
+   *          price of the book
+   */
+  public Book(String title, double price) {
     super();
     this.title = title;
     this.price = price;
   }
 
-  public BookDTO() {
+  public Book() {
     super();
   }
 

cqrs/src/main/java/com/iluwatar/cqrs/queries/IQueryService.java

@@ -3,16 +3,21 @@ package com.iluwatar.cqrs.queries;
 import java.math.BigInteger;
 import java.util.List;
 
-import com.iluwatar.cqrs.dto.AuthorDTO;
+import com.iluwatar.cqrs.dto.Author;
-import com.iluwatar.cqrs.dto.BookDTO;
+import com.iluwatar.cqrs.dto.Book;
 
+/**
+ * 
+ * This interface represents the query methods of the CQRS pattern
+ *
+ */
 public interface IQueryService {
 
-  public abstract AuthorDTO getAuthorByUsername(String username);
+  public abstract Author getAuthorByUsername(String username);
 
-  public abstract BookDTO getBook(String title);
+  public abstract Book getBook(String title);
 
-  public abstract List<BookDTO> getAuthorBooks(String username);
+  public abstract List<Book> getAuthorBooks(String username);
 
   public abstract BigInteger getAuthorBooksCount(String username);
 

cqrs/src/main/java/com/iluwatar/cqrs/queries/QueryServiceImpl.java

@@ -8,47 +8,51 @@ import org.hibernate.Session;
 import org.hibernate.SessionFactory;
 import org.hibernate.transform.Transformers;
 
-import com.iluwatar.cqrs.dto.AuthorDTO;
+import com.iluwatar.cqrs.dto.Author;
-import com.iluwatar.cqrs.dto.BookDTO;
+import com.iluwatar.cqrs.dto.Book;
 import com.iluwatar.cqrs.util.HibernateUtil;
 
+/**
+ * This class is an implementation of {@link IQueryService}. It uses Hibernate native queries to return DTOs from the
+ * database.
+ *
+ */
 public class QueryServiceImpl implements IQueryService {
 
   private SessionFactory sessionFactory = HibernateUtil.getSessionFactory();
 
   @Override
-  public AuthorDTO getAuthorByUsername(String username) {
+  public Author getAuthorByUsername(String username) {
     Session session = sessionFactory.openSession();
     SQLQuery sqlQuery = session
         .createSQLQuery("SELECT a.username as \"username\", a.name as \"name\", a.email as \"email\""
             + "FROM Author a where a.username=:username");
     sqlQuery.setParameter("username", username);
-    AuthorDTO authorDTO = (AuthorDTO) sqlQuery.setResultTransformer(Transformers.aliasToBean(AuthorDTO.class))
+    Author authorDTo = (Author) sqlQuery.setResultTransformer(Transformers.aliasToBean(Author.class)).uniqueResult();
-        .uniqueResult();
     session.close();
-    return authorDTO;
+    return authorDTo;
   }
 
   @Override
-  public BookDTO getBook(String title) {
+  public Book getBook(String title) {
     Session session = sessionFactory.openSession();
     SQLQuery sqlQuery = session
         .createSQLQuery("SELECT b.title as \"title\", b.price as \"price\"" + " FROM Book b where b.title=:title");
     sqlQuery.setParameter("title", title);
-    BookDTO bookDTO = (BookDTO) sqlQuery.setResultTransformer(Transformers.aliasToBean(BookDTO.class)).uniqueResult();
+    Book bookDTo = (Book) sqlQuery.setResultTransformer(Transformers.aliasToBean(Book.class)).uniqueResult();
     session.close();
-    return bookDTO;
+    return bookDTo;
   }
 
   @Override
-  public List<BookDTO> getAuthorBooks(String username) {
+  public List<Book> getAuthorBooks(String username) {
     Session session = sessionFactory.openSession();
     SQLQuery sqlQuery = session.createSQLQuery("SELECT b.title as \"title\", b.price as \"price\""
         + " FROM Author a , Book b where b.author_id = a.id and a.username=:username");
     sqlQuery.setParameter("username", username);
-    List<BookDTO> bookDTOs = sqlQuery.setResultTransformer(Transformers.aliasToBean(BookDTO.class)).list();
+    List<Book> bookDTos = sqlQuery.setResultTransformer(Transformers.aliasToBean(Book.class)).list();
     session.close();
-    return bookDTOs;
+    return bookDTos;
   }
 
   @Override

cqrs/src/main/java/com/iluwatar/cqrs/util/HibernateUtil.java

@@ -4,27 +4,27 @@ import org.hibernate.SessionFactory;
 import org.hibernate.boot.MetadataSources;
 import org.hibernate.boot.registry.StandardServiceRegistry;
 import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
- * 
+ * This class simply returns one instance of {@link SessionFactory} initialized when the application is started
- * @author Sabiq Ihab
  *
  */
 public class HibernateUtil {
 
   private static final SessionFactory SESSIONFACTORY = buildSessionFactory();
+  private static final Logger LOGGER = LoggerFactory.getLogger(HibernateUtil.class);
 
   private static SessionFactory buildSessionFactory() {
-    // A SessionFactory is set up once for an application!
+
-    final StandardServiceRegistry registry = new StandardServiceRegistryBuilder().configure() // configures settings //
+    // configures settings from hibernate.cfg.xml
-                                                                                              // from hibernate.cfg.xml
+    final StandardServiceRegistry registry = new StandardServiceRegistryBuilder().configure().build();
-        .build();
     try {
       return new MetadataSources(registry).buildMetadata().buildSessionFactory();
-    } catch (Throwable ex) {
+    } catch (Exception ex) {
       StandardServiceRegistryBuilder.destroy(registry);
-      // TODO HibernateUtil : change print with logger
+      LOGGER.error("Initial SessionFactory creation failed." + ex);
-      System.err.println("Initial SessionFactory creation failed." + ex);
       throw new ExceptionInInitializerError(ex);
     }
   }

cqrs/src/main/resources/logback.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="info">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>